Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue/E30, Cleveland, OH 44195, USA.
Obes Surg. 2012 Feb;22(2):240-7. doi: 10.1007/s11695-011-0509-8.
Liver steatosis can progress to fibrosis, cirrhosis, and eventually to end-stage liver disease and hepatocellular carcinoma. We thus determined the prevalence of liver steatosis and fibrosis in patients undergoing bariatric surgery using liver biopsy. We also determined the suitability of ultrasound for diagnosis of liver steatosis with and without simultaneously considering patient characteristics.
We reviewed preoperative liver ultrasound and intraoperative liver biopsy results in 451 bariatric surgery patients along with their clinical characteristics between 2005 and 2009.
Among 435 patients with conclusive biopsy results, estimated prevalence of liver steatosis was 71.5% (95% confidence interval 67%, 76%) and that of fibrosis was 27% (23%, 31%). Sensitivity of ultrasound for liver steatosis was 86% (82%, 90%); its specificity was 68% (59%, 76%). Positive predictive value of ultrasound for liver steatosis was 87% (82%, 91%), and its negative predictive value was 67% (58%, 75%). Overall diagnostic accuracy was 81% (77% 85%). Sensitivity was improved in patients with higher nonalcoholic fatty liver disease activity scores (NAS) [odds ratio (OR) 1.4 (1.1, 1.9) for a one unit increase in NAS] and prolonged duration of obesity [OR 1.3 (1.1, 1.6) for a 5-year increase in duration] but was worsen by higher body mass index.
About three quarters of bariatric surgery patients have liver steatosis, and about a quarter have fibrosis. One third of patients with liver steatosis develop fibrosis without significant clinical manifestations. Ultrasound was only moderately diagnostic for liver steatosis but was sufficient for clinical use in patients with a NAS score ≥2 and when the duration of obesity was >30 years.
肝脂肪变性可进展为纤维化、肝硬化，最终发展为终末期肝病和肝细胞癌。因此，我们通过肝活检确定了接受减重手术患者的肝脂肪变性和纤维化的患病率。我们还确定了超声在诊断肝脂肪变性时的适用性，同时考虑了患者特征。
我们回顾了 2005 年至 2009 年间 451 例接受减重手术患者的术前肝脏超声和术中肝活检结果及其临床特征。
在 435 例有明确活检结果的患者中，肝脂肪变性的估计患病率为 71.5%（95%置信区间 67%，76%），纤维化的患病率为 27%（23%，31%）。超声诊断肝脂肪变性的敏感性为 86%（82%，90%），特异性为 68%（59%，76%）。超声诊断肝脂肪变性的阳性预测值为 87%（82%，91%），阴性预测值为 67%（58%，75%）。总体诊断准确性为 81%（77%，85%）。在非酒精性脂肪性肝病活动评分（NAS）较高的患者中，敏感性有所提高[每增加一个单位 NAS，比值比（OR）为 1.4（1.1，1.9）]，肥胖持续时间较长[肥胖持续时间每增加 5 年，OR 为 1.3（1.1，1.6）]，但体重指数较高则会降低敏感性。
大约四分之三的减重手术患者有肝脂肪变性，约四分之一的患者有纤维化。三分之一的肝脂肪变性患者在没有明显临床表现的情况下发展为纤维化。超声对肝脂肪变性的诊断仅为中度，但对于 NAS 评分≥2 且肥胖持续时间>30 年的患者，其足以满足临床应用需求。
